Recently, LEDs serving as a light source are used for various purposes in terms of their longer life and energy savings. Especially during recent years, luminous efficiency of the LEDs for high-light use is improving and thus the LEDs are used for a lighting purpose.
In a case of a white LED used for the lighting purpose, the light quantity can be increased by applying a larger current to the LED. However, a performance of the LED can be degraded under such a severe condition that a large current is applied. Therefore, there is concern that the LED package and a LED module cannot have a longer life and a high reliability. For example, when an electric current flowing through the LED is increased, the heat attributed to the LED increases. Accordingly, the temperature tends to rise in the LED module for lighting and a system thereof, which can cause a deterioration of the LED module and the system. In this regard, only about 25% of the electric power to be consumed in the white LED is converted into the visible light and the rest of the electric power is directly converted into the heat. Therefore, it is required to release the heat from the LED package and the LED module. For example, various types of heat sinks are used to release the heat, wherein the heat sink may be mounted to a bottom surface of a package substrate in order to improve the heat release.
In general, the LED does not have a high resistance property against a static electricity, and thus the designs or measures for protecting the LED from such stress attributed to the static electricity may be employed (see, Patent Literature 1). For example, a Zener diode may be provided in electrically parallel connection with the LED. This can reduce the stress of the LED upon the applying of the overvoltage or overcurrent to the LED. However, in a case of a surface-mounted type LED package 200 as illustrated in FIG. 26, the Zener diode element 270 is disposed on a package substrate 210 such that it is in reversely parallel connection with the LDE element 220. The disposition of the Zener diode element 270 on the substrate makes the size of the entire package larger. That is, a further downsizing of the LED package cannot be achieved.